Sweetgrubs are insects used during the Trouble Brewingminigame, and as such are a key ingredient in the brewing of Mos Le Harmless 'rum'. Sweetgrubs live in large mounds found on both sides of the Trouble Brewing facility.

To obtain sweetgrubs, players must use the raw rat meat found in the breweries to lure them out. If the player is successful, they can then bring the grubs to their brewery and use them on the corresponding hopper. If they are not, aggressive sweetflies will appear from the hive and attack, hitting minor damage. Even if the player is successful, the mounds usually collapse after taking several grubs, forcing them to either wait or find another mound.